The present disclosure relates to a power amplifier module. In a mobile terminal that uses a communication network for cellular phones, a power amplifier module is used to amplify power of a radio frequency (RF) signal to be transmitted to a base station. In the power amplifier module, a harmonic termination circuit is used to attenuate a harmonic component of an amplified signal that is output from an amplifier (a signal having a frequency that is an integer multiple of the fundamental frequency of the amplified signal). For example, Japanese Unexamined Patent Application Publication No. 2009-302748 discloses a harmonic termination circuit that is constituted by an inductor-capacitor (LC) series resonance circuit and whose characteristics can be changed in accordance with the signal mode.
With the recent reduction in the profile of substrates on which power amplifier modules are mounted and increase in the frequencies of RF signals (for example, frequencies of about 3.5 GHz or higher), the characteristics of a harmonic termination circuit may deteriorate due to variations from element to element, which could be a problem. In this regard, in the circuit disclosed in Japanese Unexamined Patent Application Publication No. 2009-302748, the sizes of elements such as inductors and a capacitor are determined in advance and it is difficult to adjust the characteristics of the harmonic termination circuit in accordance with the variations of the elements.